Preheat your oven to 375°F (190°C) and line a baking sheet with parchment paper.

In a large mixing bowl, combine the softened butter and brown sugar, then beat them together until light and fluffy, about 2-3 minutes.

Add the egg and a splash of vanilla extract to the mixture, mixing until fully combined.

Gradually add the all-purpose flour and salt to your wet mixture, mixing on low speed until a soft dough forms.

Roll the dough into 1-inch balls and place them on the prepared baking sheet, spacing them about 2 inches apart.

Press your thumb into each dough ball to create a heart shape.

Bake for 12-15 minutes, or until edges are light golden brown.

Once baked, cool on the sheet for about 1 minute and gently redefine the heart-shaped indents.

Fill each heart-shaped indent with your chosen jam once cooled.